In our modern society, there is an increasing trend to deploy Machine-to-Machine (M2M) communications so as to automate a variety of data gathering operations and/or to provide automatic data communications in support of a variety of other automated applications increasingly demanded by consumers and service providers alike. Automated M2M communications, for example, allow utility companies to automatically read utility meters, which eliminates the need for personnel to visit customer premises and manually read meters. M2M communications also are used for alarm reporting and remote control applications. Health monitoring data can be automatically reported as well. Other applications of M2M are being developed all the time as technologies advance. Many M2M communications have utilized the public switched telephone network. However, more recently, M2M communications have begun to use communication services offered by public mobile wireless communication networks, such as operated by cellular and PCS (personal communication service) providers.
M2M applications typically involve communication of a small amount of information between an application server and multiple client devices in the field. The information exchange often is infrequent, occurring on a pre-determined schedule or triggered by infrequent events. However, at such times, the M2M data exchange generally requires near real time wireless delivery end to end. For large scale application deployments, the M2M service provider may require coast to coast wireless network coverage.
There are some present systems that piggy-back on the control channel of an older analog wireless technology for data transmission and stitch together disparate wireless network(s) to provide the required network service. This approach has very low bandwidth capacity, and limits the amount of data that can be exchanged (hence restricting the M2M applications that potentially can be supported).
Wireless carriers have developed a text messaging service known as Short Message Service or “SMS.” The SMS service transmits text messages for display on the mobile stations. In a typical implementation, SMS communications to/from a mobile station use a signaling channel over the airlink and use out-of-band signaling resources of the mobile phone network for transport to/from a server platform referred to as a SMSC (Short Message Service Center). The SMSC, for example, receives packet communications containing text messages and forwards the messages via the signaling resources and the signaling channels to the appropriate mobile stations. The SMSC will also receive similar messages from the mobile stations and forward them to servers or terminal devices accessible via an Internet Protocol (IP) packet data network. Recently there have been proposals to provide M2M communications using the SMS service through the public cellular telephone network. Several examples of proposals to use SMS for M2M type applications may be found in U.S. Pat. Nos. 6,014,089; 6,393,297; 6,900,737; and 6,990,335.
Use of the SMS technology meets the small data bandwidth and real-time transmission requirements for M2M communications, and it offers increased capacity over the prior wireless methodologies. Employing SMS also provides a wireless data solution by design. By default, it takes advantage of a nationwide SMS network infrastructure that is fully integrated, already exists and is built upon industry-standard digital wireless technology. However, actual SMS implementation must address some practical issues.
In a public wireless mobile telephone network, including networks that offer the SMS service, each wireless subscriber (whether it be an end-user or an end-device as in the case of M2M) is assigned a valid telephone number, often referred to as a Mobile Directory Number or MDN, which is used as a destination address to terminate call routing for call delivery. The MDN may also be used to identify the subscriber and verify subscription profile information during communications through the network. In developing any new wireless products or services through such a network, the MDN is nearly a mandatory requirement for implementation. However, requiring a MDN-based network service to support M2M applications has many disadvantages and will be impractical and costly to implement.
MDN numbering resources are finite. It has been a continuing challenge to wireless service providers to manage MDN usage as the number of wireless service users grow. M2M devices can potentially grow in magnitudes far beyond today's normal wireless subscriber growth. For large scale M2M applications, the numbers of new client devices can be in the millions per year. Supporting multitudes of devices can substantially add to the burden of a dwindling numbering resource pool.
The regulatory scheme also places strict restrictions on use of the MDN to support the M2M applications. MDN allocation to wireless service providers is subject to wireless number pooling and wireless number portability regulations. Number pooling requires the wireless carriers to apply for MDN blocks, a thousand numbers at a time, and requires the service providers to return a block of numbers to the pool if the utilization factor is low. Number portability allows the subscribers to take the MDN with them when they switch wireless service providers. Such numbering restrictions make it impractical to obtain a large number (millions) of MDNs to use for M2M applications. Also the number portability requirement is generally not applicable to M2M applications because the number is associated with a device and not an individual subscriber.
Hence a need exists for a viable technique to support wireless M2M network services, which will reduce or avoid any or all of the problems outlined above caused by utilizing a unique MDN or other valid telephone number for every M2M client device in order to facilitate the M2M message routing.